"The recumbent at Old Keig could be an erratic but if it is, it had been quarried before glaciation and would therefore be a unique example of Paleolithic masonry ."

Sorry -- not with you on that one. Kindly explain.

The recumbent was quarried . If it was an erratic too then the quarying would have had to have been pre Holocene and therefore before any evidence of human habitation/quarrying in that area .

You appear to be very certain on this point. Come on -- give us your evidence that it was quarried by man and not by ice. (Ice quarries blocks too -- it's rather good at it.)

Maybe you could give some evidence that it was moved by ice . Glaciation does strange things but if it was involved in this case it would have transported the stone against the direction of flow and uphill plus there are no other similar examples of this type of rock , sillamanite gneiss , as erratics in the area , and very few erratics full stop . Some areas of Britain did not have quite the same cover of ice and N Aberdeenshire is one .
Whatever the merits of the Blustones being transported by glaciation you seem to have extrapolated that thinking to anything found within the area covered by ice which is ultimately irrefutable and therefore nonscientific .